Nutrient broth medium

The strain F. oxysporum Fol007 was grown on Potato dextrose agar (PDA, Merck, Darmstadt, Germany) and a micro-conidia suspension was obtained as described in a previous study²⁴ . Briefly, under sterile conditions, fungal culture plates were flooded with sterile water and the resulting conidia suspension was filtered through filter paper to separate the micro-conidia from the mycelium. The micro-conidia suspension was concentrated by centrifugation at 3,000×g for 10 min and adjusted to a density of 10⁵ micro-conidia mL⁻¹. Infection of tomato roots by the pathogen was assessed using a specific primer pair (Forward primer: GAC GGT GTT TAT TCG GAT GG; Reverse primer: AGT TGC GCG ATA TGT GTT TG) for SIX1 gene amplification of F. oxysporum.Four beneficial bacterial strains (F10: Bacillus megaterium; F15: Bacillus licheniformis; IOF49: Bacillus sp.; OF10: Bacillus sp.) were used as a consortium in this study. The strains were selected based on their plant growth promotion effect in vivo and their antifungal activity in vitro in a previous study (data not shown). Bacterial inoculum of the four bacterial strains were prepared in 10% Nutrient Broth medium (Carl Roth, Germany) overnight. Pure cell suspensions of the four bacterial strains were washed thrice with sterile phosphate buffer (10 mM KH2PO4, pH 6.5) and adjusted to a density of 10⁶ colony forming unit (CFU) mL⁻¹.